External

• I am thinking of repainting the exterior masonry of my house that appears to have a green substance on the surface in places. Is it OK to just over paint this with Johnstone's 15 Year Smooth Masonry?
• No, the green substance you describe sounds like algae, which is carried from trees and other vegetation and gets trapped in the open pores of the masonry. Before any decoration takes place we recommend the algae is treated with Mangers Sterilisation wash prior to any redecoration.